Furnaces – Refuse incinerator – With electric heater
Reexamination Certificate
1999-01-15
2001-05-08
Lazarus, Ira S. (Department: 3743)
Furnaces
Refuse incinerator
With electric heater
C110S203000, C110S215000, C110S342000, C422S184100, C423S659000, C423SDIG001, C588S253000
Reexamination Certificate
active
06227126
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to waste treatment systems which utilize a molten reactant metal and, more particularly, to waste treatment systems in which a molten reactant metal is used to treat gaseous waste materials or waste materials which include volatile components.
BACKGROUND OF THE INVENTION
Molten metals have been used to treat hazardous materials, particularly hazardous organic materials. U.S. Pat. No. 5,000,101 to Wagner (the “Wagner Patent”) discloses a molten metal reactor and reactant metal suitable for treating organic materials. U.S. Pat. No. 4,666,696 to Schultz (the “Schultz Patent”) discloses a molten metal reactor for treating gaseous hazardous materials.
In a molten reactant metal treatment process, the molten reactant metal is contained in a reaction chamber purged of oxygen and the material to be treated is placed in contact with the molten reactant metal. As disclosed in the Wagner Patent, the molten reactant metal strips halogen atoms from organic materials, producing predominantly metal salts and liberating carbon, hydrogen, and nitrogen. Much of the carbon goes to a gaseous state and releases from the molten reactant metal along with hydrogen gas and nitrogen gas. Some metal salts may also go to a gaseous state at the temperature of the molten reactant metal, and release from the molten reactant metal. Metal atoms released from the material being treated commonly alloy with the molten reactant metal. Other elements which do not react with the molten reactant metal, along with oxides (slag), some metal salts, and some of the liberated carbon may collect at the surface of the molten reactant metal as solids or liquids.
A difficulty may arise in treating gaseous materials or materials which include volatile components. The heat of the molten reactant metal quickly volatilizes volatile components and drives off the volatilized components along with other gaseous materials to be treated. The unreacted or partially reacted gaseous products which are out of contact with the reactant metal cannot chemically react with the reactant metal. Unreacted and partially reacted gaseous materials may undergo thermal decomposition after they separate from the molten reactant metal or may react with any reactant metal vapor phase which may reside near the surface of the molten reactant metal. However, the desired reaction with the molten reactant metal requires direct contact between the unreacted and partially reacted materials and the reactant metal.
The Wagner and Schultz Patents both disclose releasing the material to be treated below the surface of the molten reactant metal. Although this ensures some contact between the gaseous material and the molten reactant metal, the gaseous material rapidly escapes to the surface of the molten reactant metal and separates to the area above the surface of the molten metal and any associated metal vapor phase. The Schultz Patent discloses a reactor having a series of chambers above a molten metal bath and a series of baffles under which the gases must pass to reach the reactor outlet. However, the molten metal bath disclosed in the Schultz Patent has little contact with the gaseous material, particularly after slag or other solid reaction products collect at the surface of the molten reactant metal.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a molten metal reactor and treatment method for treating materials which include gases or volatile components.
For convenience of description, materials to be treated in the present treatment system will be referred to in this disclosure and the following claims as “waste material.” As used herein, the term “waste material” includes any type of material which may be treated by the treatment apparatus and method according to the invention. For example, the “waste material” may include substantially any type of hydrocarbon material, particularly hazardous hydrocarbon materials such as halogenated hydrocarbons, various types of solvents, pesticides, and mixtures of these materials. A “waste material” is not in any way limited by the manner in which the material is generated or limited by the use for which the material was originally intended.
The apparatus according to the invention includes an elongated reaction chamber adapted to contain a molten reactant metal. The reaction chamber includes a gas containment boundary for trapping gases which are introduced into the reaction chamber or released from the molten reactant metal in the reaction chamber. The apparatus also includes a heater for heating a supply of reactant metal to a molten state and a circulating arrangement for circulating the molten reactant metal into and through the reaction chamber. A waste input arrangement admits waste material into the reaction chamber and a reaction product removal arrangement collects reaction products exiting the reaction chamber and contains the reaction products for removal from the system.
A mixing arrangement is associated with the reaction chamber and may include flow restricting arrangements, turbulence inducing devices, fins, weirs, baffles, or any combination of these devices. The purpose of the mixing arrangement is to mix gases contained within the reaction chamber and to mix the molten reactant metal in the reaction chamber to enhance the exposure of the unreacted gases to the molten reactant metal. This enhanced exposure allows the molten reactant metal to react fully with the unreacted gases which collect that the top of the reaction chamber below the gas containment boundary. By containing gases in the reaction chamber, particularly under an elevated pressure, by continuously circulating solid and liquid reaction products out of the reaction chamber, and by mixing both the gases and molten reactant metal at points within the reaction chamber, the treatment apparatus and method according to invention helps ensure complete reaction of gaseous waste materials.
The preferred reactant metal comprises an alloy including a large percentage of the aluminum metal. Other reactant metals which may be used in the present invention include alloys of magnesium and alloys of lithium. Regardless of the particular reactant metal employed, the reactant metal may be heated to a molten state by any suitable means including by electrical induction heating or by hydrocarbon fired burners. To prevent the reactant metal from reacting with oxygen to form oxides (slag), the molten metal is maintained in a substantially oxygen free atmosphere.
The reaction chamber is preferably mounted within a larger supply chamber containing a supply of molten reactant metal. An inlet arrangement associated with the reaction chamber provides fluid communication between molten metal in the supply chamber and molten metal in the reaction chamber. Also, the level of the molten reactant metal in the supply chamber is maintained above the level of the reaction chamber and particularly the gas containment boundary portion of the reaction chamber. The column of molten reactant metal in the supply chamber maintains a hydrostatic pressure within the reaction chamber. This hydrostatic pressure helps contain gasses in a gas containment area within the reaction chamber, below the gas containment boundary. In some forms of the invention, this hydrostatic pressure may be augmented by maintaining a positive pressure in the supply chamber in an area above the level of the molten reactant metal.
The preferred reaction chamber follows an arcuate path through the supply chamber from an inlet end to an outlet end. The inlet arrangement associated with the reaction chamber preferably includes a primary inlet opening which allows molten reactant metal to enter the inlet end of the reaction chamber. A number of secondary inlet openings are preferably spaced apart along the length of the reaction chamber. These secondary inlet openings provide additional locations where fresh molten reactant metal enters the reaction chamber, and thus improve both the circulation of molten reactant metal through the
Ciric Ljiljana V.
Clean Technologies International Corporation
Culbertson Russell D.
Lazarus Ira S.
Shaffer & Culbertson LLP
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